The present invention relates to a method of making a frozen composition utilizing an anti-freeze protein.
Frozen compositions such as ice cream, frozen yogurt, mellorine, sherbets, water ices, milk shakes, sorbets or coated novelty bars and the like, are challenging and energy intensive products to make on an industrial scale. These types of dairy desserts may range in fat content from about 0.01 to 20.0 percent by weight.
Frozen composition manufacturing includes ingredients such as condensed skim milk, cream, sweeteners such as corn sugar, cane sugar, corn syrups and water which are blended together in a vessel and are pasteurized, homogenized and cooled to a temperature of 32.degree. to 42.degree. F. The mix is then stored under agitation at 32.degree. to 40.degree. F.
Liquid flavoring may be added to the pasteurized frozen composition mixture. Particulates such as fruits and nuts may be added during freezing by a device such as a fruit feeder. Once flavored, the mixture is frozen and extruded under air pressure in a scrape-surface heat exchanger for air incorporation and is packaged at about 18.degree. to 25.degree. F.
After being packaged and, in some cases wrapped, the frozen composition is hardened in a hardening tunnel, hardening box, or hardening freezer or in a contact plate freezer at a temperature of -30.degree. F. to -60.degree. F. The hardening process has conventionally been used to freeze remaining unfrozen water in the frozen composition after it has been aerated, agitated and partially frozen.
The hardening step involves quickly freezing the composition to obtain a desired frozen composition mouthfeel. Mouthfeel is affected by the size of ice crystals within the frozen composition. Larger ice crystals impart a grainy mouthfeel. Consequently, rapid freezing results in smaller ice crystals and smoother frozen composition mouthfeel. Without the hardening step, liquid water in frozen composition compositions freezes at much slower rates and forms large ice crystals which impart unacceptably grainy mouthfeel to the frozen composition.
During frozen storage, ice crystal size increases over time as disproportionation occurs and smaller crystals melt and recrystallize onto larger ice crystals in a dynamic process resulting in pronounced iciness, giving the product an undesirable characteristic. Controlling the ice crystal size, whether by formulation, processing, distribution temperature control, or product age management is an objective of all frozen composition manufacturers in order to ensure a high quality finished product.
The Huang et al. reference U.S. Pat. No. 5,175,013, that issued Dec. 29, 1992, describes a frozen composition that includes an ingredient relating to a reduction in ice crystal formation. The ingredient is a high molecular weight starch hydrolysate.
The DuRoss patent U.S. Pat. No. 5,324,751 which issued Jun. 28, 1994, describes microcrystals of sorbitol and mannitol. The sorbitol microcrystals serve as cryoprotectants.
The Warren et al. patent U.S. Pat. No. 5,118,792, which issued Jun. 2, 1992, describes polypeptides that have anti-freeze properties.